Introduction: How to Make a Transparent Audio Reference XL Speaker Cable
For my first project here on Instructables, I thought I'd start with what I think is about the coolest DIY project for high-end audio buffs. This instructable will show you how to make a pair of $12,500 Transparent Audio Reference XL speaker cables for less than 200 bucks. My project is based on a schematic I found on the internet, along with photos and x-rays of the insides of the Transparent Audio network box (see step 10 for everything I found). Here are the parts you'll need:
½” black corrugated split tube, 20 ft. - $23.88
12/4 wound high strand count copper speaker wire, 20 ft – $11.20
½” black braided nylon tube, 20 ft. - $19.00
Plastic project boxes, 2 ea – $7.94
14 gauge copper wire, 10 ft - $7.59
Gold plated brass spades, 8 ea - $6.00 (I found them on eBay)
1” black heat-shrink tube, 2 ft. – $6.96
½” black heat-shrink tube, 4 ft – $11.12
½” red heat-shrink tube, 4 ft – $11.12
1000 picofarad capacitors, 2 ea - $2.12
31.7 ohm resistors, 2 ea - $1.15
½” oak dowel, 4” - $35.00 (for 36” dowel)
Black hot glue sticks, 3 ea – $3.94
Flux-core solder, 1 roll - $29.97
Here are the tools you'll need:
Hot glue gun
Heat gun (or hair dryer)
Masking Tape (I used a lot of it to help me stabilize things while I was working on them)
Razor knife or Xacto
Step 1: Preparing the Cable
I'm just going to explain how to make one wire. To make a pair, just double the instructions (obviously). :)
First, cut a ten foot length of your 12/4 wire and strip off the outer jacket. You can discard the jacket as you won't need it at all. Use masking tape to make sure that the twist of the cable stays the way it is.
Next, strip the ends of all the wires back about three quarters of an inch. In my case, I had red, white, black, and green coated wires. You will use two wires for each "leg" of the cable. So, twist the ends of the red and white wires together. Do the same thing for the black and green ones. The red/white will be the positive leg and the black/green will be the negative. Once you've got them twisted together, tin the ends so they'll stay that way while you're handling the cables.
Next, find the center of the wire (5 feet from either side) and cut the positive leg. Strip back the insulation where you just cut, combine the wires and tin them the way you just did with the ends. This center cut is where you will later add one of Transparent's "networks."
Step 2: Prepare the Network Box
Set aside your cable for a minute and pick up your network boxes. The plastic project boxes can be purchased at Radio Shack. I chose the boxes that measure 5.75" by 2.75" by 2". You could go smaller, but these will give you plenty of room to work inside them.
Mark the center point of the ends of the boxes. Then, drill a hole in each end so your cable can go through the box. The hole should be slightly smaller than 1/2 inch. I drilled a pilot hole and then used a "stepping bit" to fine tune the hole. Just take a short length of your corrugated tubing to test whether your hole is the right size. The tubing should fit snugly.
Step 3: Build the Main Network
Transparent's main "network" is simply an inductor measuring 2.5 micro Henries that is soldered into the path of the positive leg of the cable.
To make the inductor, take a two inch long piece of your oak dowel and wind your 14 gauge solid copper wire tightly around the dowel. In order to get precisely 2.5 micro Henries, you will need something more complex than a multimeter. I went to my buddy's shop and used his LCR meter to measure mine.
Side note: My opinion is that you don't have to make it too precise because a 2.5 micro Henry inductor really doesn't add very much inductance anyway. When I measured the cable without the inductor soldered in, it measured 3 micro Henries by itself. So, without the inductor, if I wanted to add 2.5 micro Henries of inductance, I just needed to lengthen the cable by about 8 feet. Anyway, back to the instructions.
I found that if I wound tightly, I consistently got 2.35 to 2.55 micro Henries with 18 turns around the dowel. I think that's a good rule of thumb to go by if you don't have a complex instrument to measure the inductor.
Once you're satisfied with your inductor, use masking tape to hold it in place around the dowel. Tin the ends so they'll be easy to solder later.
Step 4: Solder in the Network
All you have to do here is solder in the inductor to the positive side of the cable and then fish the cable through the holes in your box.
It's easy to fish with no jacket on the wires and if you do it this way you don't run the risk of burning the box with your soldering iron.
Step 5: Dress Up the Cable
Now that you have your main network complete, you can add some dressing to your cable to make it look nice and to protect it from wear and tear.
Take a five foot piece of your corrugated split tubing and wrap it around the cable on one side of the network box. Then, take your nylon braid and slide it over the tubing. Once it is at the end of the tubing next to your network box, gently work both layers through the hole in the box. Once you've got them inside the box, use a zip tie and hot glue to keep them from sliding out again. I like to use the black hot glue because of the lower melting point, which makes it more liquid that the standard stuff. That way, you can work it around the cable to make sure it fills in any gaps between your braid and the hole in the box.
Repeat the process for the other side of the cable.
Step 6: The Output Network
You may not have known this, but there is another, much smaller network on the output end of the Transparent Reference XL speaker cable. It consists of a 1000 pF capacitor and a 31.7 ohm resistor.
All you do here is solder the cap and resistor together. Then, use your soldering iron to melt away the insulation on the positive and negative legs of the cable 12 inches from the output end. Using your soldering iron, solder together both wires of each leg and leave yourself a little "knob" to solder the network to.
The capacitor is soldered to the negative leg, and the resistor is soldered to the positive leg.
Once the solder has cooled slide a piece of the larger heat-shrink tubing over the network and apply some heat with a heat gun or hair dryer. This will simply protect the network.
In order to do this step without damaging the tubing and nylon braid, I just moved them back a bit so they were out of the way.
At this point it's a good idea to take a pencil and draw an arrow on the main network box indicating the signal flow. Like I said before, the small R/C network that we made should be attached to the output end, making the cable directional.
Step 7: Finishing the Ends
Take your spades and solder them to the ends of the cable. I used a bench clamp to help me do it easily.
Now, take your smaller heat-shrink tube and slide them over your spades. A red one should be used on the positive side and a black one on the negative side. Make sure the heat-shrink overlaps onto the spade. This will give some strain relief and it makes it look better. Apply heat.
Notice that I didn't slide the heat-shrink on before I soldered on the spades. I did it this way because heating the spades with your soldering iron takes a long time and causes the copper in the wire to heat up. This can cause the tubing to shrink on you before you're ready for it. So, get some spades that are small enough to slide your tubing over.
Next, take a piece of the larger black tubing (about 4 inches) and shrink it around where the tails come out of the corrugated/braided tubing. Apply some heat to it, but be careful because if it gets too hot, the nylon braid will burn.
Repeat this process on both sides of the cable.
Step 8: Finish It Up and Burn It In
Now all you have to do is attach the cap to the main network box. I took a sharpie and wrote "in" and "out" on the bottom of the box so I wouldn't forget which way to hook up the cables. I'll do something more permanent later.
I didn't do this yet, but you may want to fill your network box with hot glue. I'm told that this will make it so the inductor won't vibrate as much (vibrations can cause noise). It will also make the network boxes heavier, making them lay on the ground better.
To burn in the cables, just hook them up to your rig and let it play for a few days. If you have a cable cooker, that might speed up the process.
Step 9: Conclusion
I hope you found this project as fun to do as I did. I've had them hooked up to my system for a couple of weeks now and they sound fantastic.
You may have asked yourself where I got the plans to build them. Well, the internet is full of photos of Transparent cables that have been broken apart. One of the sites that published these photos had a schematic of the design based on measurements the person took as he was taking apart the cable. I'll attach the photos I found to the next step of this instructable.
Though it may not be an exact duplicate, I'd match my cables against genuine Transparent cables any day of the week. Especially when you consider that they cost less than 2% of the original... and they sound fabulous!